DOE contracted with a engineering firm to prepare detailed cost estimates for facility engineering, design, and construction. The cost estimates included definitive engineering work, design verification, and other facility support functions, but did not include costs related to land acquisition, site testing, cost escalation, or sales taxes. DOE officials identified additional costs, such as state and local taxes and annual impact assistance to local governments. DOE used the contractor's estimates as a basis for its cost projections and developed nine program elements that it considered necessary for an MRS facility. GAO found that: (1) DOE may have underestimated the proposed operating costs of MRS by 10 to 15 percent; (2) the costs that DOE excluded from the estimate could be of substantial magnitude; (3) according to the fee adequacy report, the current fee is adequate to offset system life-cycle costs; and (4) DOE officials believe that the cost to integrate MRS into the total waste management system will be less than $2.9 billion because MRS will provide benefits to the total system, such as decreased transportation costs and a reduction of spent-fuel handling facilities at the repository, which will partially offset the cost of the facility.